1. Technical Field
The present invention relates to a liquid crystal device and to a projection display device.
2. Related Art
In recent years, liquid crystal projectors (projection display devices) have been used as display devices in which large-screen display can be performed. In such a projector, a structure has been suggested in which a liquid crystal device, which is driven in a ‘VA (Vertical Alignment) mode’ where liquid crystal having negative dielectric anisotropy is vertically aligned on a substrate and liquid crystal molecules are tilted by applying a voltage, is included as a light valve. However, since most liquid crystal projectors in the related art have a contrast ratio of substantially 1:500 in a projected image, they are not as good as projectors, such as DMDs (registered trademark) using mechanical shutters, which have a contrast ratio of 1:3000. That is because of the viewing angle characteristics of the liquid crystal device. In the liquid crystal projector, light incident on the liquid crystal device is not entirely parallel light. However, since the liquid crystal device has incident angle dependence, it causes the contrast ratio of the projected image to decrease. To overcome this problem, Japanese Unexamined Patent Application Publication No. 7-69536 discloses a technology in which an optical compensating plate is employed to compensate for the incident angle dependency of the liquid crystal device, thereby realizing a display having a higher contrast.
In the technology disclosed in Japanese Unexamined Patent Application Publication No. 7-69536, a refractive index anisotropic body serving as the optical compensating plate is arranged in a vertical-alignment-type liquid crystal cell, so that it is possible to compensate for a phase difference occurring in the liquid crystal cell due to inclined light. However, when the liquid crystal is pretilted to control the alignment of liquid crystal molecules, the effect of the optical compensating plate decreases as the pretilt angle decreases from 90°.